• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.1
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• pp.75-84
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• 2011

The e-learning contents offered in the current educational system does not appropriately reflect the needs of actual users in the planning and development phases. Considering this problem, this study sets the following four topics as its research: Stability of e-learning; Obstacles of the applications of e-learning; e-learning contents that users wants to be offered besides lectures; and methods of e-learning, and based on these goals, it aims at determining the 'needs of the users for the promotion of e-learning. As the target of the study, a survey was conducted with 200 students who have experienced taking e-learning classes in four universities located in Eastern Seoul, which have introduced an e-learning system. The data collected from the survey went through data coding and data cleaning processes and were analyzed by year, major, and department using SAS 9 statistics package program. The result of this study showed that developing and offering services of e-learning contents that are customized to students based on their majors and year can become an effective plan for promoting e-learning.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4419-4435
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• 2015

The use of an efficient packet scheduling scheme for a forward link in satellite communication networks is very important to support fairness for each return channel satellite terminal (RCST) and the service differentiations for user traffics. To support fairness and QoS for each RCST with service-level agreement (SLA), the Adaptive Coding and Modulation (ACM) system in a satellite hub has to process packets with considering modulation and coding (MODCOD) and packet types. Although a DVB-S2 system with ACM scheme has higher transmission efficiency, it cannot offer fairness or quality of service (QoS) to RCSTs. Because the data are transmitted with high MODCOD in regions with clear skies, while data are transmitted using low MODCOD in regions experiencing rain events. In this paper, we propose a two-step scheduling scheme offering fairness and QoS to RCSTs, while minimizing a decrease in throughput. The proposed scheme is carried out performance evaluations using a computer simulation. As results of this simulation, the proposed scheduler was shown to support bandwidth fairness to an individual RCST, and provide a level of QoS differentiation for user traffics.

• Research in Mathematical Education
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• v.14 no.2
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• pp.173-194
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• 2010

This study examines the differences and similarities of mathematics teachers' subject matter knowledge among England, the Chinese mainland and Hong Kong. Data were collected from a ten-item test in the SKIMA subject matter audit instrument [Rowland, T.; Martyn, S.; Barber, P. & Heal, C. (2000). Primary teacher trainees' mathematics subject knowledge and classroom performance. In: T. Rowland & C. Morgan (eds.), Research in Mathematics Education, Volume 2 (pp.3-18). ME 2000e.03066] from over 500 participants. Results showed that participants from England performed consistently better, with those from Hong Kong being next and then followed by those from the Chinese mainland. The qualitative data revealed that participants from Hong Kong and the Chinese mainland were fluent in applying routines to solve problems, but had some difficulties in offering explanations or justifications.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.5
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• pp.2067-2080
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• 2016

Cooperative spectrum sensing (CSS) for vacant licensed bands is one of the key techniques in cognitive radio networks. Currently, sequential probability ratio test scheme (SPRT) is considered as a powerful soft decision approach to improve the sensing result for CSS. However, SPRT assumes all secondary users (SU) are honest, and thus offering opportunities for malicious SUs to launch the spectrum sensing data falsification attack (SSDF attack). To combat such misbehaved behaviors, recent efforts have been made to trust mechanism. In this paper, we argue that powering SPRT with traditional trust mechanism is not enough. Dynamic SSDF attackers can maintain high trust in an alternant process of submitting honest or false sensing data, resulting in difficultly detecting them. Noting that the trust value of dymamic SSDF attackers behave highly volatile, a novel trusted SPRT scheme (VSPRT) based on volatility decay analysis is proposed in this paper to mitigate the harmful effect of dynamic SSDF attackers in the process of the soft-decision data fusion, and thus improving the accuracy of the final sensing result. Simulation results show that the VSPRT scheme outperforms the conventional SPRT schemes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10B
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• pp.1117-1123
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• 2009

Head fixed type multi-focus display system using Galvano-scanner and DMD(Digital Micro-mirror Device), which is able to perfectly accommodate, can solve eye fatigue due to conflict between convergence eye movement and accommodation action in stereoscopic display. This system is able to accommodate through making convergence point about each view point and offering it in front of observer's pupil by using laser scanning method. In this paper, we analyzed laser scanning method of this multi-focus display system. And multi-focus display system based on this analysis was made, which showed that focus adjustment was possible through video camera. As a result, formation principle of view point of multi-focus system by laser scanning method was verified.

• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.275-283
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• 2006

Writers enroll their outcome to Program Deliberation & Mediation Committee and get the copyright preserved for the protection of IPR. The program registration is conducted through off-line and on-line methods, and especially on-line registration provides program registrants convenience along with the safety of property from external copyright invaders. However, it is a shortcoming that the integrity and confidentiality of the enrolled program cannot be guaranteed in case of internal factors such as system errors, administrator's illegal access and revision. This paper proposes the reliable system, ensuring programs and offering convenience of Digital signature management from the system errors and intruding factors by internal administrator, using the security of confidentiality, integrity and Multi-Signature Scheme for program.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.2
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• pp.181-193
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• 2020

The midst competition makes a brand all together with its offering products and services is becoming a crucial element for company existence. This requires direct involvement from internal organizational to develop effective strategic branding. According to Asosiasi Penyelenggara Internet Indonesia (APJII), Indonesia's internet penetration is among the highest in Asia. The purpose of this research is to improve the strategic role of brand orientation within Internet Service Provider (ISP) for maximizing return on the company's financial and non-financial benefits by proposing organization change readiness variable. The data collection is taken using an online survey with a non-parametric sampling method and collected 68 qualified respondents for data analysis using SEM-PLS (Structural Equation Modeling with Partial Least Square). The result indicates partial hypotheses on the constructed model between variables brand orientation, brand commitment, and internal brand equity is acceptable. Another finding is stated hypotheses on organization change readiness as moderation is not accepted and means there is no significance to the constructed model. The main conclusion resumes associative human memory can shape up organization change readiness inside internal toward then brand. Relevant cues generate information received in the human brain then will create common associative and becoming social identity on internal brand equity.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.6
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• pp.29-36
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• 2005

RFID(Radio Frequency Identification) will be used for recognizing things and offering distinctive information in Ubiquitous environment. But we are not ready to provide security service to RFID. Therefore we propose the approach of safe RFID system which provides the solution for eavesdrop, forgery, and modification based on Pre-Distribution protocol and RC5 security algorithm. First We distributes the secret key to the Tag with the Reader that is major subject on RFID system using Pre-Distribution protocol. Then we will provide to various security services and privacy protection using RC5 security algorithm. The proposed safe RFID system simulated on ATmega128 evaluate environment.

• Journal of Ubiquitous Convergence Technology
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• v.2 no.1
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• pp.51-55
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• 2008

A digital home is a ubiquitous environment that is expected to be realized in the near future. All information appliances in a house are connected to each other through wired and/or wireless home networks. Authenticated user can access the various services provided by the digital home, and the access is not restricted by equipment, time, or location. The technologies that form the digital home can be grouped into two categories: wired networking technologies and wireless networking technologies. For the purpose of ubiquitous environments, wireless-networks offer suitable and seamless high-quality services. A wireless LAN can be created simply by equipping a single access point. For that reason, the cost of establishing such a network is low and using it is easy. Of course, there is an exciting new wireless technology. It is the Ultra Wide Band (UWB). However, it is not enough to bring wireless convenience, although offering a broad range of high-speed data transfer capabilities, Because of unstable. Thus, of the wireless-networking systems, we focus on the wireless LAN. We quantitatively analyze its capabilities. The dynamic and adaptive wireless LAN provides a foundation for the evolution toward the next generation of wireless and adaptive networks. The difference between wired LAN and wireless LAN in upload and download rates is small. Although the wireless LAN experiences a greater loss rate than the wired LAN, the difference is minimal. We conclude that a wireless LAN is suitable for use in an apartment environment.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.9 no.3
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• pp.198-205
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• 2009

In this paper, design of framework architecture of pervasive computing system providing seamless inter space interactions between private and public smart spaces is presented. The seamless inter space interaction issues are related to establishing user's service environment by allocating relevant resources in a new location where there are no prior settings for the user or where there are current users already being served in the new location. In the realm of pervasive computing, we can have different types of smart spaces, offering proactive and intelligent services, which are islands of smart spaces independent from each other. As users move about, they will have to roam from private smart space to public smart space and vice versa. When they enter a new island of smart space, they will have to setup their devices and service manually to get the same or different services they had at the previous location. Users might be living in a non-pervasive computing environment because this manual operation is inappropriate to its generic features of proactive and intelligent services of pervasive computing. The framework architecture will provide seamless inter space interactions initiated by changes in users' location to acquire negotiations of resources for new and current residents regarding service provision with limited available networked devices.